Diols containing aromatic moieties are valuable as intermediates for the synthesis of polyesters. For example, bisphenol-A is known to yield polyesters having high glass transition temperatures.(See, for example, Reinking, et al., J. Appl. Polymer Sci., 7, 2153 (1963).) It is generally accepted by those skilled in the art that modifications of polyesters, particularly polyethyleneterephthalate (PET), can best be accomplished by copolymerization of a diol with terephthalic acid and ethylene glycol as opposed to copolymerization of a diacid with terephthalic acid and ethylene glycol. Diols that are structurally rigid are believed to raise the glass transition temperature of the PET when copolymerized, that is, when some of the ethylene glycol is replaced with the diol. Few rigid diols are available. Examples include 2,2,4,4-tetramethylcyclobutanediol, cyclo-pentanediol, and bisphenol-A.